This invention generally relates to organopolysiloxane compositions which cure at room temperature to a variety of resins.
Room temperature vulcanizable (RTV) silicone rubbers which have crosslinked in the presence of moisture are easy to handle and have improved weathering and electrical properties. On account of these advantages, they find use in a variety of applications, for example, as sealing materials in building and construction fields and adhesives in electric and electronic fields. In particular, oxime-elimination type RTV silicone rubbers are widely utilized as sealing material in building and construction fields because they are fully weather resistant. For substrates of resins, alcohol-elimination type RTV silicone rubber are utilized because they are compatible with resins.
Similarly for the bonding and securing of electric and electronic parts, a variety of adhesive compositions have been proposed. As the durability of resins improves in these years, there arise many cases where conventional sealing materials fail to provide a bond. There is a desire to have an RTV silicone rubber composition having an improved adhesiveness.
An object of the invention is to provide an RTV organopolysiloxane composition which cures into a product having improved adhesiveness to a variety of resins and which can be used as building sealants and adhesives for bonding and securing electric and electronic parts.
Attempting to develop an RTV organopolysiloxane composition which is effective as an adhesive sealing material applicable to resins, the inventor has found that an organopolysiloxane composition obtained by blending an organopolysiloxane with a silane compound having at least two hydrolyzable groups each attached to a silicon atom in a molecule or a partial hydrolyzate thereof and the addition reaction product between a vinyl group-bearing bisphenol A skeleton compound and an organoxy or mercapto group-bearing silicon compound cures into a product having drastically improved adhesiveness in that it is bondable to those resins which are believed to be difficult to bond in the prior art, typically polybutylene terephthalate, high impact polystyrene, and acrylic resins. This composition is effectively utilizable as a building sealant and an adhesive for many resins, typically for use in the bonding and securing of electric and electronic parts.
The present invention provides an RTV organopolysiloxane composition comprising (A) 100 parts by weight of an organopolysiloxane of the following general formula (1) or (2), (B) 0.1 to 30 parts by weight of a silane compound having at least two hydrolyzable groups each attached to a silicon atom in a molecule or a partial hydrolyzate thereof, and (C) 0.1 to 10 parts by weight of the addition reaction product between a compound of the following general formula (3) or (4) and a compound of the following general formula (5) or (6).
HO(SiR12O)nHxe2x80x83xe2x80x83(1)
Herein R1 is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, and n is an integer of at least 10. 
Herein R1 and n are as defined above, R2 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, R3 is a monovalent hydrocarbon group of 1 to 6 carbon atoms, and m is equal to 0 or 1. 
Herein R4 and R5 each are hydrogen or methyl, R6 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, R7 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 8 carbon atoms, a and b each are equal to 0 or 1, c is equal to 1, 2 or 3, d is equal to 1 or 2, the sum of c+d is equal to 3 or 4, and x is an integer of 1 to 8.